When the coal mining era came to an end, large industrial areas in Germany’s Ruhr district were abandoned and many of them had to find a new direction. While decision-makers were still discussing how to tackle the situation, nature had already decided and many of the abandoned mines became beautiful wooded areas. The mine tracks, now covered with trees and bushes, form a perfect corridor for the movement of species from one site to another, contributing to increased biodiversity in these areas known as “urban forests”.